Repair Of Heat-Damaged RC Slabs Using Fibrous Composite Materials

Sixteen under-reinforced high strength concrete one-way slabs were cast, heated at 600o C for 2h, repaired, and then tested under four-point loading to investigate the coupling effect of water recurring and repairing with advance composite materials on increasing the flexural capacity of heat-damaged slabs. The composites used included high strength fiber reinforced concrete layers; and carbon and glass fiber reinforced polymer (CFRP and GFRP) sheets. Upon heating then cooling, the RC slabs experienced extensive map cracking, and upward cambering without spalling. Recuring the heatdamaged slabs for 28 days allowed recovering the original stiffness without achieving the original load carrying capacity. Other slabs, recured then repaired with steel fiber reinforced concrete (SFRC) layers, regained from 79% to 84% of the original load capacity with a corresponding increase in stiffness from 382% to 503%, whereas those recured then repaired with CFRP and GFRP sheets, regained up to 158% and 125% of the original load capacity with a corresponding increase in stiffness of up to 319% and 197%, respectively.